Centering tool



y 1941 H. A. s. F'oRNEuus I 2,243,201

CENTERING TOOL Filed Jan. 18, 1940 Fig. i9 E g. F

Patented May 27, 194i UNET STATES 2 Claims.

My invention relates to improvements in centering tools whereby the center of a shaft, rod or bar may be readily and accurately found.

An object of the invention is to provide a new and convenient means for locating the center of a shaft or the like;

A further object of the invention is to provide means for scoring or marking lines on the end surface of a shaft, bar or rod, or the like;

A further object of the invention is to provide holding and positioning means for a guide for scoring or marking lines;

Further objects and advantages of the invention will be apparent from the following description.

I accomplish these and other objects by the invention herein described, preferred embodiments of which are illustrated in the accompanying drawing, in which Figure l is a plan view of my improved centering tool;

Figure 2 is a side view of the same;

Figure 3 is a side view of a modified form of a centering tool, and

Figure 4 is a side view of the same.

Similar characters of reference refer to like parts throughout the several views.

The form of the device illustrated in Figures 1 and 2 comprises a pair of crossed arms I and 2, which swing on a double headed pivot stud 3. The free ends 4 and 5 respectively of the arms I and 2, are bent inwardly toward each other similar to the usual calipers. The opposite ends 6 and I of the arms I and 2 are pivoted to links 8 and 9 which carry a double headed stud II] slideable in a slot II in an arm I2 which is mounted on the arms I and 2 by the pivot stud 3. The arm I2 is preferably spaced from and carried in parallel alignment with the plane of the arms I and 2 by means of washers I3, I4. The arm I2 is thus always disposed above and equidistant from the free ends of the arm I and 2. In the free end of the arm 12 there is provided a longitudinal guide slot I5. A scriber I6 preferably of hard metal and having a sharp point I! and of a size to fit closely within the slot I5 and to be drawn therethrough, as hereinafter explained, may be carried, when not in use, in a pocket I8 in the base of the arm I2.

The tool, being thus assembled, is adapted for use in the following manner: The two ends 4 and 5 of the arms I and 2 are brought against the marginal edge of the shaft, bar or rod I9 the center of which is to be found, and the free end of the arm l2, which is spaced above the plane ofthe arms I and 2, will then rest upon the end surface of the shaft, bar or red I9, with its longitudinal guide slot over the diameter thereof. Th extremities of the arms I and 2 may be pro vided with cut out seats 29, if desired, to facilitate the accurate positioning of the said arms with respect to the marginal edge of the shaft I9. The scriber I6 is then drawn across the end surface of the shaft I9 and a line drawn through V the guide slot I5 which will cross the center of the said shaft I9. The tool is then rotated or moved to a position approximately at right angles to the first above mentioned position, and a second line is drawn by the scriber in like manner as above described. The meeting point of the two lines, thus drawn, will be the center to be found.

In the modified form of the device illustrated in Figures 3 and 4, an arm 2I is provided at its free end with a longitudinal guide slot 22, and carries a Y-plate 23, the arms 24, 25 of which are bent away from the free end of the arm 2| and spaced therefrom in parallel relation thereto.

In this last mentioned form of the device, the two arms 24, 25 are pressed against the marginal edge Section of the shaft, bar or rod I9 with the slotted end of the arm 2| resting upon the end surface thereof.

The hard metal scriber I9 is then drawn through the guide slot 22 thereby making a diametric mark or scratch across the end surface of the said shaft I9. The tool is then rotated or moved to a position approximately at right angles to the first above mentioned position and a second line is drawn in like manner by the scriber and the meeting point of the two lines so drawn will be the center to be found.

Having thus described my invention, what I claim is:

1. A centering tool comprising, in combination, a pair of pivotally connected crossed arms each having their free ends and base ends respectively turned toward each other, seats at the free ends of the said crossed arms for an object to be, centered, pivot mean-s connecting the said crossed "arms at approximately the medial point between their ends, a third arm mounted intermediate its ends on the said pivot means and having its ends positioned equi-distant from the free ends and the base ends respectively of the said crossed arms and having a guide slot for a scriber on its free end, and spacing links between the base ends of the said cross arms and of the said third arm whereby the said. third arm its ends on the said crossed arms and having its ends positioned equi-distant from the respective ends of the crossed arms, a guide for a scriber in the free end of the said third arm, and spacing means between the base of the said crossed arms and the base of the said third arm whereby the said third arm is positioned equi-distant from the free ends of the said crossed arms when they are rotated on their said pivot means.

HENRY A. G. FORNELIUS. 

